Incandescent electric lamp and lamp-socket



(No Model.)

B. FORD. INCANDBSCENT ELECTRIC LAMP AND LAMP SOCKET.

Patented Aug. 16,1892.

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UNITED STATES PATENT OFFICE.

BRUCE FORD, OF GLOUCESTER, NEV JERSEY.

INCANDESCENT ELECTRIC LAMP AND LAMP-SOCKET.

SPECIFICATION forming part of Letters Patent No. 481,019, dated August16, 1892.

Application filed November Z7, 1891. Serial No. l113,201. (No model.)

To all whom t may concern.-

Bc it known that LBRUOE FORD,of Gloucester, in the county of Camden andState of New Jersey, haveinvented an Improvement in Electric Lamps, ofwhich the followingis a specification.

My invention has reference to electric lam ps and it consists of certainimprovements which are fully set forth in the following specificationand shown in the accompanying drawings, which form a part thereof.

My invent-ion has particular reference to automatic cut-outs forincandescent lamps designed to be worked in series.

The object of my invention is to provide a construction in which theshort-circuiting fusible plug or substance is arranged in the lampproper in place of being arranged in the socket or key.

In carrying out my invention I provide one or both terminals of the lampwith a destructible substance of high resistance which offers sufficientresistance to the current during the normal operation of the lamp toinsure the proper proportion of the current passing through the filamentof the lamp, but which upon the rupture of the carbon filament of thelamp will become destroyed or fused by the excessive current forcedthrough it and permit the closing of the circuit by means of metalliccontacts. The metallic contact may take place directly through thespring-contacts in the socket, as in the case of the removal of thelamp, or through contact of one of the spring-contacts with one terminalof the lamp which is in contact with the other spring-contact within thesocket-piece.

Referring to the drawings, Figure 1 is a sectional elevation of thesocket-piece with the lamp shown in elevation in connection therewithand embodying my invention. Fig. 2 is a similar view of the same withthe lamp slightly removed from the socket-piece. Fig. 3 is a sectionalplan View of the socket-piece on line a: and Figs. 4 and 5 show otherforms of bases for the lamps, such as those in common use, with myimprovement applied thereto.

A is the socket-piece, and may be formed of any suitable material and inany manner desired.

B is the electric lamp, and may be of any construction found suitable,various kinds of lamps already in the market being adapted to theemployment of my invention.

In the construction shown in Figs. 1 and 2, C and D are the terminals,and these are formed like two pins extending down from the base of thelamp, provided with annular grooves E and recessed at the bottom, as atF, in which recess the high-resistance material f is inserted. Thishigh-resistance material f may be such as is Well known in themarket-for instance, a mixture of vulcanized rubber and graphite orprepared paper. It is immaterial what this material is so long as itforms a high-resistance path to the current for the purpose of causing asufficient current to pass through the filament of the lamp, and yet atsuch a time to be of such a composition that it will be fused ordestroyed the instant the filament becomes broken.

lVithin the socket I have the bindingposts H and R, connecting with thetwo terminals of the line-circuit.

P are two springcontacts connect-ing with the binding-posts andA adaptedto be brought into contact by the action of akey N, of hard rubber,having a cam n, of metal, adapted to press the said spring-contacts Ptogether to cut the lamp out of active circuit, or at least put it inshunt relation, which destroys its luminosity, owing to the highresistance of the filament and low resistance of the circuit through thecontacts I).

G and L are two spring-contacts respectively connected to thebinding-posts H and R, and also support the key N for simplicity, thoughthis is not essential. The upper part of the spring-contact G isstamped, as shown in Fig. 3, so as to form a curved edge K as a boundaryof the slot, the finger I arranged below the slot and the lip J. Thespringcontact L is formed with a slot and curved edge M, but has nofinger I or lip J.

Vhen the lamp is thrust into the socket, the grooves E in the terminalsC and D respectvely receive the curved edges M and K of the contacts Land G, as shown in Fig. 1, and the edges of the terminals D press uponthe finger I, producing a tendency to thrust the lip J upward and at thesame time cause IOO the spring-contact Gto be moved to the right toinsure better contact. The terminal C of the lamp has its highresistance at the base of the terminal caused to press upon the lip J,and its groove E receives the edge M of the spring-contact L. Theelasticity of the contacts L and G with reference to the grip upon theterminals C and D may be regu lated by means of the adjusting-screw S,which extends through the contact G into the key N. When the lamp is outof the socket, the spring-contacts G and L come together, as shown inFig. 2, thereby completing the linecircuit without reference to theoperation of the key N. It the lamp is in place, as shown in Fig. l, theturning of the key will throw the lamp into shunt relation and continuethe current in the line without the interposition of the resistance ofthe carbon filament of the lamp. If the filament should becomedestroyed, the current will force its way through the high-resistancematerial F, causing it to become fused and permit the lip J to come inContact with the metal of the terminal C, thus completing a metallicline-circuit. The spring contacts L and G may be so proportioned thatthe upward movement of the lip J may permit them to come into contactdirectly, as shown in Fig. 2, though this is not essential. With thelamp shown in Figs. l and 2 the terminals C and D are alike, andconsequently the lamp may be turned so that either terminal may beconnected with the positive contact of the socketpiece.

In the cases of the lamps shown in Figs. 4 and 5 we have two well-knownforms of terminals. C and D in these figures also correspond to theterminals of the lamp, and in both cases the terminal C projectsdownward and is formed with a recess f, in which the high-resistancematerial F is placed. The spring-contacts G and L would be slightlymodiiied to suit these well-known forms of lamp-bases; but in principlethey would remain the same. In this case there would be no necessity forthe employment of the groove E.

It is immaterial to my invention, considered broadly, what the minordetails of construction may be, as these details would be modified withthe adaptation of my invention to any of the well-known forms of lampsin the market. The principle in all cases would remain the same-that isto say, the lamp proper would carry the high-resistance fusible ordestruetible material andthe socket part would be provided with aspring-coutact arranged to press upon the high-resist ance fusible ordestructible material of the lamp, while otherwise embodying` the chielprinciples of the socket-pieces in incandescent series lighting.Therefore, while I pre- Ier the construction shoWn,I do not limit myselfthereto.

I'Iavin g new described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

l. An electric lamp having two terminals, one of which is provided witha high-resistance substance capable of destruction upon the passage ofan excessive current, in combination with a lamp-socket provided with aspring-contact adapted to electrical contact with one of the terminalsof the electric lamp and pressing upon the high-resistance substance otthe other terminal.

2. As an article of manufacture, an incandescent lainp having its basepart provided with two terminals and a high-resistance substance inelectrical connection with one of said terminals and capable ofdestruction upon the passage of an excessive current through it, incombination withalamp-socket provided with a spring-contact adapted toelectrical contact with one of the terminals of the electric lamp andpressing upon the high-resistance substance of the other terminal.

3. An incandescent lamp having its base provided with two terminals, oneot' which projects downward, is adapted to extend within thesocket-piece, is recessed upon its end, and contains a high-resistancefusible or destructible substance.

4. As an article of manufacture, an incandescent lamp having its basepart provided with two terminals and a high-resistance substancemechanically supported by and in electrical connection with one of saidterminals, capable of destruction upon the passage of an excessivecurrent through it, in combination with a socket-piece having contactsfor conneetion with the contacts of the lamp when iitted to thesocket-piece and in which one of said contacts is provided with aspring-extension or lip adapted to press upon the high-resistancematerial for the purpose of forming metallic contact about the lamp uponthe destruction of the said high-resistance material.

5. The combination of an incandescentlamp having two terminals,high-resistance substance capable ot destruction or fusion, mechanicallysupported by and electrically connected with one terminal of the lamp,and a socket-piece adapted to receive the lamp and provided withcontacts connecting, respectively, with the terminals of theline-circuit and the terminals of the lamp and in which one of saidcontacts has a spring-extension on one-ot the contacts of thesocket-piece, resting normally against the high-resistance substance ofthe lamp.

6. 'lhe combination of an incandescentlamp having two terminals, ahigh-resistance substance capable of destruction or fusion, mechanicallysupported by and electrically connected with one terminal of the lamp,asocketpiece adapted to receive the lamp and provided with contactsconnecting, respectively, With the terminals of the line-circuit and theterminals of the lamp, one of said contacts Ion ITO

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having a spring-extension resting normally against the high-resistanoesubstance of the lamp, and a out-out sWiteh arranged Within thesocket-piece for shunting the lamp Without the destruction of itsfilament.

7. An electric lamp having terminals C and D, formed with grooves E,combined with a support, springeontaets G and. L, connecting with theterminals of the line, the former being provided with the edge K, thefinger I, and lip J and the latter with the curved edge M, and ahigh-resistance destruotible substance arranged between the lip J andthe terminal C of the lamp.

S. An electric lamp having terminals C and D, formed with grooves E,combined With a BRUon FORD.

Witnesses:

ERNEST HOWARD HUNTER, C. M. DIETTERICH.

